1st- Shackler is a great skill; melee assassins won't want to go near you, and if you get on top of a ranged character they might as well get a soda. It also builds nicely in your tier six talent. Backlash is viable, but Shade is best avoided.

2- Jailors is the only choice for this build. Two more skeletons right on top of your enemy is great, and the tier 3 ability makes it an instant heal as well.

3- Rathma's Blessing synergizes well with Jailors, and makes it so you can stay in lane nearly indefinitely. Gives more dependable healing than Harvest, and the added staying power will increase your damage potential more than Weaken.

4- Skeletal Mages is my personal preference. It slows both fleeing and charging enemies and gives them a difficult decision. If they scatter, you can pick off the weakest, and if they stand their ground your team will make easy work of the whole group. Also a great way to escape a pesky chaser.

5- Decrepify seems to be the weaker option here, but keeping an enemy off of you is always a good thing with this hero. When you get Executioner however, you will be grateful for any chance to slow an enemy.

6- Executioner is the moment that Xul goes from annoyance to deadly threat. With Shackler and Decrepify you can almost always deal 40% additional damage to your prey. This is the lynch pin of the build and will allow you to harvest your foul crops.

7- Bone Spear is a solid choice for this build. Am extra damage cooldown is a great thing to have. Tier 7 more than any is a personal choice: if they have an annoying healer Mortal Wounds is a great choice, and if your team fights always go your way Raised Mage can turn a double kill into a Mega Kill.

Bone Armor: Before Executioner bone armor is best used as an escape, or in a team fight. Once you reach level 16 it can then be used offensively.

Spectral Scythe: Line it up on a minion wave, or drop it behind an enemy hero, this attack is great. Many players forget about Xul's range and won't fully disengage while low, so you can drop your scythe right on them. With Decrepify, and Executioner you can use it to make your foes even more vulnerable.

Cursed Strikes: Great in any fight, it can be used to scatter an enemy team, clear a whole minion wave, or wreck a tower. Again, Executioner makes it vicious.

Bone Prison: The delay on this ability may seem like a negative, but if you can predict when an enemy hero is going to disengage, this ability can give you a free kill. Best used on flight risks or annoying tanks.

Skeletal Mages: A line of risen frost mages that slow and damage, this ability will turn the tide in many of your team fights. The mages can be easily dispatched by heavy AOE attacks, such as Gazlow's Grav-O-Bomb 3000, so try to bait out any heavy AOE attacks before you use it. It's also good for covering an escape or solo contesting an objective.

Xul is best when surrounded by his skeletal minions. While soaking just make sure he always has minions around him. If you can bait an assassin into jumping you Bone Prison and a friend in the bushes is always a great idea. Xul is surprisingly durable, but is still a specialist: don't try to solo towers and try not to be caught alone. If someone gets the drop on you, use Bone Prison and Bone Armor to secure your escape. In a teamfight stay on the peripheral of the melee zone and do all you can to slow and damage your enemies. Being caught on the wrong side of a fight is almost certain death.

If you keep these thoughts in mind and play Xul like the killer he is, you're gonna like the way you pwn.